Implement modern C++ features

## Brief feature description

Sadly most of the modern C++ features are not available to use since they either use C++17 or later or have undefined behavior, exceptions or heap behind the scenes. This issue shall track new useful language features from C++ or maybe even Rust and check if they can be implemented in C++14.

- [ ] `std::filesystem::exists()`

Start by locating the C++14 compatibility code or entry point related to std::filesystem::exists(). Determine whether this feature can be supported without C++17, undefined behavior, exceptions, or heap use, and verify that the resulting behavior matches the requested existence check.

Written by the indexing model from the issue text.